Ion Beam Methods for the Synthesis, Modification, and Characterization of Radiation Detection Materials
EMSL Project ID
22592a
Abstract
Inorganic scintillators have been used for the detection of ionizing radiation in numerous applications for over a century, current users are, however, restricted to a handful of commercially available products, which do not meet evermore demanding technical requirements. In order to understand the underlying processes occurring in novel materials now proposed as scintillators and solid-state detectors, one must carefully control and characterize the detector material properties and the associated interactions with ionizing radiation. As an illustrative example, one may consider the scintillator, ZnO:X (where X represents a variety of potential dopants including Ga, Al, In, etc.). ZnO:Ga was first reported as a fast scintillator. ZnO scintillators, however, suffer from scintillation light yields in terms of the number of emitted luminescence photons per MeV of excitation that are relatively low in comparison with a number of other scintillator materials. Recent testing of ZnO:Ga in both powder and single crystal form using pulsed x-rays and alpha particle excitation has demonstrated the promise for developing an outstanding inorganic scintillator based on ZnO that would combine fast timing characteristics, high light output, and the intrinsic robust ZnO thermal and mechanical properties. In order to realize the promise and potential of ZnO-based radiation detectors, there is a need to significantly increase our current level of understanding of the operative doping mechanisms and the role played by impurities or sample treatments that can potentially produce improved the scintillation characteristics in zinc oxide.
This work seeks to achieve an improved understanding and control of the atomic-level structural, dynamic, and transport properties of novel materials intended for use as ionizing radiation detectors. The work will focus on surface/interface properties, including the atomic-level controlled doping of scintillator materials and surface preparation studies of solid-state radiation detectors.
Specifically, we are proposing to utilize ion implantation and various ion beam techniques to first dope the near surface region of ZnO single crystals with Ga, In, or Al and to then characterize the displacive-radiation-induced structural damage and dopant depth profiles. RBS/channeling and elastic recoil detection analysis (ERDA) techniques will then be used to study the distribution of the ion-implanted dopants and the annnealing of surface damage subsequent to thermal processing of the ion-implanted material. The response of ion-implantation-fabricated ZnO detectors to alpha particles will be characterized in terms of their light yield and response time at EMSL Ion Lab. Ion implantation will be used to fabricate ZnO detectors in which various levels of Ga, In, or Al are incorporated in the ZnO near-surface region, and the performance of the resulting detectors will be correlated with the doping levels and dopant distributions as a function of depth below the crystal surface. Variable-energy implants will be utilized to achieve doping depths that correspond as closely as possible to the range of the alpha particle radiation of interest.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-05-31
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members